Habitat utilization and winter time-activity budgets of the whooper swan Cygnus Cygnus (Linnaeus, 1758) population wintering at the Van Lake Basin, Turkey

Abstract

In this study, daily behaviour patterns of whooper swans (Cygnus cygnus) were studied at the Van Lake Basin, which is one of the most important wintering areas of the species in Turkey. Winter-time activities of the swans were monitored from sunrise to sunset in 6 different categories: resting, feeding, preening, walking on land, swimming and flying. The most common daytime activity was resting (55%). Feeding (12.48%) and preening (10.98%) were the two other main diurnal activities of whooper swans during the present study. Resting peaked in midday period (08:30-13:30) while feeding was observed frequently in early morning hours (06:00-8:30) and late afternoon (13:30-17:00). At the beginning of severe winter period (December and January) whooper swans clearly reduced feeding time in all parts of the day, probably because they still met metabolic demands. A significant increase in feeding behaviour was observed in January and February when they were preparing to migrate. While open water surface was the most preferred area for resting, shallow coastal areas and reeds were the most utilized foraging habitats.